1. Field of the Invention
This invention relates to manhole cover supports for placing over and raising the effective grade of an existing manhole cover-receiving structure, and more particularly, to anchors for anchoring manhole cover supports to manhole cover-receiving structures.
2. Description of the Related Art
Ordinarily, a manhole cover support is used when a roadway is resurfaced with an added layer of paving material. A manhole cover support raises the level of the manhole cover to the new street level. Frequently, manhole cover supports are anchored to the manhole frame. A typical prior art anchor is simply a strap of metal which is bolted to a threaded hole in the manhole cover support at its upper end. The lower end is angled to reach beneath a flange which is formed in the manhole frame. A bolt which is threaded through the lower end of this strap contacts the underside of the flange to tighten the anchor. In other words, when the bolt is rotated, the strap is pulled downward to anchor the manhole cover support to the frame.
Installation of the prior art anchor straps requires that a worker hold the strap in position with one hand, and thread the upper screw into the manhole cover support with the other. Often times, the bolt and/or the strap and/or the wrench are dropped into the sewer pipe below. There is a need for a simple, speedy positive means of connecting the anchor straps with the manhole cover support to simplify installation and reduce the frequency of dropping parts.
Another problem utility companies face is that some manhole covers have downwardly extending reinforcement members on their underside. These reinforcement members sometimes interfere with conventional anchor straps and prevent their use. To replace the manhole cover with another non-interfering type is often prohibitively expensive. Thus, there is a need for a locking device which avoids interference with this type of manhole cover.